# 预留参数
![](https://support.huaweicloud.com/distributed-devg-v2-gaussdb/public_sys-resources/note_3.0-zh-cn.png)
下列参数为预留参数，该版本不生效。
acce_min_datasize_per_thread
cstore_insert_mode
dfs_partition_directory_length
enable_fstream
enable_hdfs_predicate_pushdown
enable_orc_cache
schedule_splits_threshold
enable_constraint_optimization
enable_hadoop_env
enable_hypo_index
undo_space_limit_size
undo_limit_size_per_transaction
undo_zone_count
ustore_attr
enable_ustore
walwriter_cpu_bind
#### 废弃函数
enable_adio_debug
enable_adio_function
enable_fast_allocate
prefetch_quantity
backwrite_quantity
cstore_prefetch_quantity
cstore_backwrite_quantity
cstore_backwrite_max_threshold
fast_extend_file_size
effective_io_concurrency